CH482406A - Low-toxicity pesticides and a process for the production of the active ingredients to be used as the active component - Google Patents

Description

  

  



   Low-toxicity pesticides and a process for the preparation of the active ingredients to be used as the active component
The invention relates to new low-toxicity pesticides which, as active ingredients, contain compounds of the formula
EMI1.1
 and a process for the production of these active ingredients to be used as active components.



   In this formula, R ', R ", R"' denote hydrogen, halogen or a lower alkyl radical, Rt to R6 optionally substituted alkyl, cycloalkyl, aralkyl, aryl or heterocyclic radicals, where Rt to Rss can be identical or different . X has the meaning S or 0.



   It has been found that pesticides that act as the active component are compounds of the formula
EMI1.2
 contain, in which R ', R ", R"' hydrogen, halogen or a lower alkyl radical, Rj to R6 optionally substituted alkyl, cycloalkyl, aralkyl, aryl or heterocyclic radicals, where Rj to R6 can be identical or different , and X represents a sulfur or oxygen atom, has an extremely low toxicity to warm-blooded animals with good insecticidal effect and plant tolerance.

   While the toxicity of most of the known and already commercially available thio- or dithiophosphoric acid esters, for example, is between 2.3 and 500 mg / kg rat perorally, the thio- or dithiophosphoric acid esters produced by the process according to the invention still show when administered orally 5000 to 10,000 mg / kg rat showed no symptoms of poisoning.



   The new compounds to be used as the active component in low-toxicity pesticides according to the invention are prepared by adding 1 mol of a 1,3,5-tris-acryloyl-hexahydro-s-triazine of the formula which is easily accessible from acrylonitrile or substituted acrylonitrile and formaldehyde
EMI2.1
 in which R ', R ", R"' denote hydrogen, halogen or a lower alkyl radical, is added onto 3 mol of identical or different corresponding thiol or thionothiol phosphoric acid esters. The addition of 1,3,5-tris-acryloyl-hexahydro-s-triazines to phosphoric acid esters of the above general constitution already takes place at room temperature with a positive exotherm.

   The reaction is preferably carried out at a temperature in the range from 20 to 150 ° C. and in the presence of inert solvents or diluents such as chloroform, dimethylformamide, benzene, acetonitrile, acetone, methyl ethyl ketone. The addition can be accelerated by adding catalytic amounts of a tertiary amine such as triethylamine and the like. In addition, a polymerization retarder such as hydroquinone can also be used in order to prevent polymerization of the 1,3,5-tris-acryloyl-hexa-hydro-s-triazines.



   According to the process described, the esters are obtained in very good yields and with a high degree of purity as partly light yellow and practically odorless oils, partly also as colorless crystalline substances.



   The active compounds according to the invention are used in the formulations customary for pesticides, for example as dusts, scattering agents or sprays, optionally also in combination with other active compounds.



   example 1
EMI2.2

47.4 g (0.3 mol) of dithiophosphoric acid-O, O-dimethyl ester are converted at 25 ° C. with stirring to a solution of 24.9 g (0.1 mol) of 1,3,5-tris-acryloyl-hexahydro Triazine, 0.2 g of hydroquinone and 0.3 ml of triethylamine are added dropwise to 200 ml of chloroform, the temperature rising to about 60 ° C. The mixture is left to stir at 60 ° C. for a further 2 hours and, after cooling, washed with 100% strength Soda solution and water, dried with sodium sulfate, filtered and distilled to a residue in vacuo, giving 65 g (91% of theory) of the new ester as a pale yellow, viscous oil.



   Example 2
EMI2.3

24.9 g (0.1 mol) 1,3,5-tris-acryloyl-hexahydro-s-triazine are dissolved in 150 ml of chloroform. With stirring, 55.8 g (0.3 mol) of dithiophosphoric acid O, O-diethyl ester are added at 20 ° C., the temperature rising to about 55 cm. The mixture is stirred for a further 3 hours at 50 ° C. and the solvent is distilled in vacuo The oily residue is washed with 100% sodium carbonate solution and water, a thick crystal slurry being formed. 68.5 g (85 ovo of theory) of colorless crystals are obtained recrystallized from ethanol, mp 58 ° C.



  Example 3
EMI2.4

To a solution of 24.9 g (0.1 mol) of 1,3,5-tris-acryloyl-hexahydro-s-triazine, 0.1 g of hydroquinone and 0.3 ml of triethylamine in 200 ml of chloroform, with stirring at 20 C 64.2 g (0.3 mol) of dithiophosphoric acid O, O-diisopropyl ester were added dropwise. The mixture is heated to 70 ° C. for a further hour and worked up as in Example 1. 82 g (92% of theory) of the new ester are obtained in the form of a pale yellow oil. Example 4
EMI3.1

24.9 g (0.1 mol) 1,3,5-tris-acryloyl-hexahydro-s-triazine are dissolved in 150 ml of chloroform.

   51 g (0.3 mol) of O, O-diethyl thiol phosphoric acid ester are added dropwise at 25 cm. The temperature rises to 50 cm. The mixture is heated to 60 to 70 ° C. for a further 3 hours and worked up in the customary manner. 47 g (63 o / o of theory) of the new ester are obtained as a yellow oil.



  Example 5
EMI3.2

14.5 g (0.05 mol) 1,3,5-tris- (a-methyl-acryloyl) -hexahydro-s-triazine are suspended in 70 ml acetone. At 20 ° C., 23.7 g (0.15 mol) of dithiophosphoric acid O, O-dimethyl ester are added with stirring.



  After a short time, with a temperature rise of up to about 35 ° C., a clear solution occurs. The mixture is stirred for 4 hours at 50 to 60 cm and worked up in the usual way.



  27 g of the new ester are obtained as a pale yellow viscous oil. Yield: 71% of theory.



   Example 6
The insecticidal testing of some selected compounds was carried out on flies (Musca domestica) and on grain weevils (Sitophilus granarius) in acetone solution (details of the amount of active ingredient in ug / cm2), on rice flour beetle larvae (Tribolium confusum) as the active ingredient in wheat flour (details of the percentage of active ingredient in the flour ).



   The degree of effectiveness was recorded on grain weevils and flies after an exposure time of eighteen hours and on rice meal beetle larvae after ten days of exposure.



   The following table provides information about the biological effectiveness of some products obtained according to the invention.

 

Claims (1)

Compound Application Amount of active ingredient Effect against (in jug / cm2 degrees or / o) (in / o) according to example 1 M. domestica 12.5 100 T. confusum 0.2 100 according to example 5 M. domestica 12.5 100 T. confusum 0.5 100 according to Example 4 M. domestica 12.5 100 S. granarius 130 90 T. confusum 0.5 100 PATENT CLAIMS I. Low-toxicity pesticides, characterized in that the active component is a compound of the formula EMI3.3 in which R ', R ", R"' are hydrogen, halogen or a lower alkyl radical, Rt to RG are optionally substituted alkyl, cycloalkyl, aralkyl, aryl or heterocyclic radicals and X is sulfur or oxygen, the compound being symmetrical or may be asymmetrical. II. A process for the production of low-toxicity pesticides according to claim I, characterized in that 1 mol of an unsaturated compound of the general formula EMI4.1 where R ', R ", R"' are hydrogen, halogen or a lower alkyl radical, are reacted with 3 moles of the same or different corresponding thiol or thionothiol phosphoric acid esters and the products obtained are used as the active component. SUBCLAIMS 1. The method according to claim II, characterized in that the reaction is carried out in the presence of a solvent or diluent. 2. The method according to claim II, characterized in that the reaction is carried out at a temperature of 20 to 150 "C. 3. The method according to claim II, characterized in that the reaction is carried out in the presence of a tertiary amine as a catalyst. 4. The method according to claim II, characterized in that the reaction is carried out in the presence of a polymerization retarder.